ORIGINAL RESEARCH
mActive: A Randomized Clinical Trial of an Automated mHealth Intervention for Physical Activity Promotion Seth S. Martin, MD, MHS; David I. Feldman, BS; Roger S. Blumenthal, MD; Steven R. Jones, MD; Wendy S. Post, MD, MS; Rebeccah A. McKibben, MD, MPH; Erin D. Michos, MD, MHS; Chiadi E. Ndumele, MD, MHS; Elizabeth V. Ratchford, MD; Josef Coresh, MD, PhD; Michael J. Blaha, MD, MPH
Background-—We hypothesized that a fully automated mobile health (mHealth) intervention with tracking and texting components would increase physical activity. Methods and Results-—mActive enrolled smartphone users aged 18 to 69 years at an ambulatory cardiology center in Baltimore, Maryland. We used sequential randomization to evaluate the intervention’s 2 core components. After establishing baseline activity during a blinded run-in (week 1), in phase I (weeks 2 to 3), we randomized 2:1 to unblinded versus blinded tracking. Unblinding allowed continuous access to activity data through a smartphone interface. In phase II (weeks 4 to 5), we randomized unblinded participants 1:1 to smart texts versus no texts. Smart texts provided smartphone-delivered coaching 3 times/day aimed at individual encouragement and fostering feedback loops by a fully automated, physician-written, theory-based algorithm using realtime activity data and 16 personal factors with a 10 000 steps/day goal. Forty-eight outpatients (46% women, 21% nonwhite) enrolled with a meanSD age of 588 years, body mass index of 316 kg/m2, and baseline activity of 96704350 steps/day. Daily activity data capture was 97.4%. The phase I change in activity was nonsignificantly higher in unblinded participants versus blinded controls by 1024 daily steps (95% confidence interval [CI], 580 to 2628; P=0.21). In phase II, participants receiving texts increased their daily steps over those not receiving texts by 2534 (95% CI, 1318 to 3750; P1 minute. Additionally, we assessed participant satisfaction through an online survey, with qualitative and quantitative elements, upon trial completion.
Statistical Analysis We estimated that the sample size needed to detect at least a 2000-step difference in means was 14 participants per group, or 42 participants total, assuming a within-participant SD of 1800 steps/day, 2-sided alpha of 0.05, and beta of 0.8. Allowing for 12% attrition, target enrollment was 48 participants. Our trial aimed to detect an increase of 2000 steps/ day, given that this was previously associated with a 10% relative reduction in the long-term incidence of CVD,17 and is generally felt to represent a clinically significant increase. However, the selection of 2000 steps/day does not signify that a smaller increase in physical activity could not also be clinically significant. Baseline characteristics were summarized using descriptive statistics—frequency (percentage) for categorical data and mean (standard deviation) for continuous data. All outcomes were compared between treatment arms by intention to treat. We used repeated measures analysis of variance for mean comparison tests and calculated 95% confidence intervals (CIs). For comparisons of proportions, we used Fisher’s exact test because of small cell sizes. Exploratory subgroup interaction testing was performed to DOI: 10.1161/JAHA.115.002239
examine for heterogeneity in treatment effect by age, sex, race, body mass index (BMI), diabetes, hypertension, dyslipidemia, coronary heart disease (CHD), dog ownership, marital status, employment, or baseline activity. Statistical analyses were performed using Stata software (version 11.1; StataCorp LP, College Station, TX).
Reporting We followed the Consolidated Standards of Reporting Trials of Electronic and Mobile HEalth Applications and onLine TeleHealth (CONSORT-EHEALTH).18 Most elements are reported here, with additional details on CONSORT-EHEALTH items provided in Table S3.
Results Participant and Data Flow The trial flow diagram is shown in Figure 1. Of 50 eligible individuals, 48 (96%) enrolled. There was no early dropout and all participants in the intervention arms completed the protocol. One blinded participant had data transmission issues in phase II and elected not to complete the protocol. Daily activity data capture was 97.4%.
Baseline Characteristics There were no significant baseline differences between groups (Table 1). Overall, participants were age 588 years, nearly evenly split by sex, and 21% nonwhite. Eighty-eight percent were employed, primarily in management and professional occupations. The majority of participants were obese, 23% had diabetes, and 29% CHD. Baseline activity levels were 96704350 steps/day, 9345 min/day, and 1318 aerobic min/day.
Primary Outcome: Change in Steps/Day Physical activity trajectories were different among the 3 trial groups. The blinded group showed a progressive downward trend over the whole time period, particularly in the change from phase I to II. This downward drift was not observed in either of 2 other trial groups. The unblinded arm trajectory was characterized by a maintenance of baseline activity levels, whereas the biggest shift in trajectory was noted in the text-receiving arm. This group had a clear upward trend in physical activity in response to smart texts. In phase I (Table 2), blinded control participants obtained a mean of 616 fewer steps/day (6% decrease) whereas unblinded participants increased their steps/day by a mean of 408 (4% increase). The between-group differential was Journal of the American Heart Association
3
ORIGINAL RESEARCH
tracking to surpass their step goal. According to the preprogrammed algorithm, smart texts were sent 3 times/ day (morning, mid-day, and evening), with exact times customized to the participant’s usual wake time, lunch time, and beginning of evening leisure time. On the day of enrollment, all participants completed an online questionnaire (Table S1) to provide information on 16 personal and clinical characteristics, which was later used for personalizing text messages within the texting arm. Specific examples of text messages are shown in Table S2.
mActive Trial
Martin et al ORIGINAL RESEARCH
Figure 1. mActive trial flow diagram. IPAQ indicates International Physical Activity Questionnaire, Long-Form. nonsignificantly higher in the unblinded group versus blinded controls by 1024 steps/day (95% CI, 580 to 2628; P=0.21). In phase II (Table 2), the blinded group further decreased its activity by 1042 steps/day (11% decrease) whereas the unblinded–no texts group decreased by 200 steps/day (
mActive: A Randomized Clinical Trial of an Automated mHealth Intervention for Physical Activity Promotion Seth S. Martin, MD, MHS; David I. Feldman, BS; Roger S. Blumenthal, MD; Steven R. Jones, MD; Wendy S. Post, MD, MS; Rebeccah A. McKibben, MD, MPH; Erin D. Michos, MD, MHS; Chiadi E. Ndumele, MD, MHS; Elizabeth V. Ratchford, MD; Josef Coresh, MD, PhD; Michael J. Blaha, MD, MPH
Background-—We hypothesized that a fully automated mobile health (mHealth) intervention with tracking and texting components would increase physical activity. Methods and Results-—mActive enrolled smartphone users aged 18 to 69 years at an ambulatory cardiology center in Baltimore, Maryland. We used sequential randomization to evaluate the intervention’s 2 core components. After establishing baseline activity during a blinded run-in (week 1), in phase I (weeks 2 to 3), we randomized 2:1 to unblinded versus blinded tracking. Unblinding allowed continuous access to activity data through a smartphone interface. In phase II (weeks 4 to 5), we randomized unblinded participants 1:1 to smart texts versus no texts. Smart texts provided smartphone-delivered coaching 3 times/day aimed at individual encouragement and fostering feedback loops by a fully automated, physician-written, theory-based algorithm using realtime activity data and 16 personal factors with a 10 000 steps/day goal. Forty-eight outpatients (46% women, 21% nonwhite) enrolled with a meanSD age of 588 years, body mass index of 316 kg/m2, and baseline activity of 96704350 steps/day. Daily activity data capture was 97.4%. The phase I change in activity was nonsignificantly higher in unblinded participants versus blinded controls by 1024 daily steps (95% confidence interval [CI], 580 to 2628; P=0.21). In phase II, participants receiving texts increased their daily steps over those not receiving texts by 2534 (95% CI, 1318 to 3750; P1 minute. Additionally, we assessed participant satisfaction through an online survey, with qualitative and quantitative elements, upon trial completion.
Statistical Analysis We estimated that the sample size needed to detect at least a 2000-step difference in means was 14 participants per group, or 42 participants total, assuming a within-participant SD of 1800 steps/day, 2-sided alpha of 0.05, and beta of 0.8. Allowing for 12% attrition, target enrollment was 48 participants. Our trial aimed to detect an increase of 2000 steps/ day, given that this was previously associated with a 10% relative reduction in the long-term incidence of CVD,17 and is generally felt to represent a clinically significant increase. However, the selection of 2000 steps/day does not signify that a smaller increase in physical activity could not also be clinically significant. Baseline characteristics were summarized using descriptive statistics—frequency (percentage) for categorical data and mean (standard deviation) for continuous data. All outcomes were compared between treatment arms by intention to treat. We used repeated measures analysis of variance for mean comparison tests and calculated 95% confidence intervals (CIs). For comparisons of proportions, we used Fisher’s exact test because of small cell sizes. Exploratory subgroup interaction testing was performed to DOI: 10.1161/JAHA.115.002239
examine for heterogeneity in treatment effect by age, sex, race, body mass index (BMI), diabetes, hypertension, dyslipidemia, coronary heart disease (CHD), dog ownership, marital status, employment, or baseline activity. Statistical analyses were performed using Stata software (version 11.1; StataCorp LP, College Station, TX).
Reporting We followed the Consolidated Standards of Reporting Trials of Electronic and Mobile HEalth Applications and onLine TeleHealth (CONSORT-EHEALTH).18 Most elements are reported here, with additional details on CONSORT-EHEALTH items provided in Table S3.
Results Participant and Data Flow The trial flow diagram is shown in Figure 1. Of 50 eligible individuals, 48 (96%) enrolled. There was no early dropout and all participants in the intervention arms completed the protocol. One blinded participant had data transmission issues in phase II and elected not to complete the protocol. Daily activity data capture was 97.4%.
Baseline Characteristics There were no significant baseline differences between groups (Table 1). Overall, participants were age 588 years, nearly evenly split by sex, and 21% nonwhite. Eighty-eight percent were employed, primarily in management and professional occupations. The majority of participants were obese, 23% had diabetes, and 29% CHD. Baseline activity levels were 96704350 steps/day, 9345 min/day, and 1318 aerobic min/day.
Primary Outcome: Change in Steps/Day Physical activity trajectories were different among the 3 trial groups. The blinded group showed a progressive downward trend over the whole time period, particularly in the change from phase I to II. This downward drift was not observed in either of 2 other trial groups. The unblinded arm trajectory was characterized by a maintenance of baseline activity levels, whereas the biggest shift in trajectory was noted in the text-receiving arm. This group had a clear upward trend in physical activity in response to smart texts. In phase I (Table 2), blinded control participants obtained a mean of 616 fewer steps/day (6% decrease) whereas unblinded participants increased their steps/day by a mean of 408 (4% increase). The between-group differential was Journal of the American Heart Association
3
ORIGINAL RESEARCH
tracking to surpass their step goal. According to the preprogrammed algorithm, smart texts were sent 3 times/ day (morning, mid-day, and evening), with exact times customized to the participant’s usual wake time, lunch time, and beginning of evening leisure time. On the day of enrollment, all participants completed an online questionnaire (Table S1) to provide information on 16 personal and clinical characteristics, which was later used for personalizing text messages within the texting arm. Specific examples of text messages are shown in Table S2.
mActive Trial
Martin et al ORIGINAL RESEARCH
Figure 1. mActive trial flow diagram. IPAQ indicates International Physical Activity Questionnaire, Long-Form. nonsignificantly higher in the unblinded group versus blinded controls by 1024 steps/day (95% CI, 580 to 2628; P=0.21). In phase II (Table 2), the blinded group further decreased its activity by 1042 steps/day (11% decrease) whereas the unblinded–no texts group decreased by 200 steps/day (
